/** Proofs GPU - Space and Time's cryptographic proof algorithms on the CPU and GPU.
 *
 * Copyright 2023-present Space and Time Labs, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
#include "sxt/base/device/active_device_guard.h"

#include "sxt/base/device/state.h"

namespace sxt::basdv {
//--------------------------------------------------------------------------------------------------
// constructor
//--------------------------------------------------------------------------------------------------
active_device_guard::active_device_guard() noexcept { prev_device_ = get_device(); }

active_device_guard::active_device_guard(int device) noexcept {
  auto dv = get_device();
  if (device == dv) {
    prev_device_ = -1;
  }
  prev_device_ = dv;
  set_device(device);
}

//--------------------------------------------------------------------------------------------------
// destructor
//--------------------------------------------------------------------------------------------------
active_device_guard::~active_device_guard() noexcept {
  if (prev_device_ == -1) {
    return;
  }
  set_device(prev_device_);
}
} // namespace sxt::basdv
